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Report on Subsurface Environmental Exploration (Soil Borings) Page 11 A & M Market, 4579 East Acampo Road, Acampo, California November 9, 1992 Quorum Environmental Consultants, Inc , Project 92-120-2 ' 6.0 CONCLUSIONS ' Based on the results of the laboratory analyses and observations made during this and previous studies, we conclude the following fSampling of soil from the test pits in the west side of the base of the tank cavity showed that TPHg in the range of 600 to 1,300 ppm is present in ' soil at 22 feet deep • Soil from the borings is free of detectable hydrocarbons, therefore, the ' bonngs on the west side of the tank cavity and nearest to it (borings B-2 and B-3) define the lateral extent of hydrocarbons Based on observed, apparent hydrocarbon odors made during the drilling, the zone in which hydrocarbons may remain appears to be from 15 to between 26-112 and ' less than 30 feet deep • Soil from the stockpile has no hydrocarbons within the laboratory detection Nlimits • If hydrocarbons in soil are limited to 30 feet or less in depth, thea they will be at least 30 feet above the reported ground-water levels in the area 7.0 RECOMMENDATIONS ' We recommend that the remaining soil in the tank cavity that may contain hydrocarbons be removed by excavation We suggest that this be done by excavating a ramp into the cavity from the north side, subexcavating to approximately 27 feet deep from the test pit ' area west, and extending laterally to the north-south line defined by borings B-2 and B-3 to the west of the pit Soil from the ramp excavation should be carefully stockpiled in a separate area so that it remains isolated from any apparently contaminated materials and will not require sampling and testing Soil samples should be collected from the base and sidewall of the newly excavated area and submitted to the laboratory for analysis for TPHg and BTEX; we recommend that two samples from the base and two from the west ' sidewall at about 25 feet below grade be analyzed. We also recommend that these analyses be performed onsite by a mobile analytical laboratory so that the tank cavity may be backfilled with all stockpiled soil confirmed to be free of hydrocarbons as soon as possible Extreme caution must be used in this excavation because the soil is subject to localized sloughing. Expedience is also important because this work is to be performed during the rainy season As Quorum has previously submitted a work plan for the prior